Devices for scanning tooth models so as to obtain a data set which digitally represents the tooth model are known. Such data sets can be used for the automatic production of dental prosthesis elements.
If different data sets each only represent part of a model and if the two data sets have, however, an area in which they overlap and represent the same part of the model, the two data sets can be combined by a matching process. The data in the overlapping area are used for defining or ascertaining the relative arrangement of the individual data sets. The data sets normally represent the shape of a surface in three dimensions. Hence, said matching is referred to as 3D matching. This matching can also be used for combining a larger number of data sets, e.g. 5, 10, 15 or 20 data sets, so as to obtain a single data set.
Tooth models can be provided in the form of so-called split-cast models. These models comprise a model part holder and removable model parts. The individual model parts correspond to individual portions of a model of a set of teeth, e.g. to one or a plurality of teeth or tooth sites. When the model parts are held by the model part holder, they represent a set of teeth or parts thereof. The model part holder defines the position of the individual model parts relative to one another.
A normal set of teeth of an adult comprises 32 tooth sites, 16 in the upper jaw and 16 in the lower jaw. Each tooth site is normally occupied by a tooth. A tooth site may, however, also be occupied by a dental prosthesis element or by parts of such an element or by implants or parts of such implants, such as implant abutments, or a residual tooth area or a gingival area. A tooth gap normally results in a gingival area at the tooth site. A tooth may also comprise dental prosthesis elements, such as fillings, inlays, overlays or the like. A residual tooth area can be a damaged tooth or a tooth prepared by the dentist (ground). A plurality of tooth sites can also be occupied by a dental prosthesis element, e.g. a bridge.